A great number of pharmaceutic agents is used in today's medical practice to treat infections. These infections quite frequently impair the immunological system while a weakened immunological system, on the other hand, attracts infections.
As infections are frequently characterized by an accelerated progress of the disease because pathogens multiply exponentially, it is desirable to have therapeutic agents on hand that are suited for initial medication due to their wide activity spectrum.
This requirement is currently met only to a limited extent with regard to bacterial infections. Most bacterial infections can be treated with .beta.-lactam antibiotics like, for example, penicillines or cephalosporines. However, those antibiotics can not be used to treat infections caused by certain species of bacteria like Legionella or Mycoplasma. So far, only tetracyclines or macrolids are used to treat infections caused by these bacteria. Thus, the choice of antibiotics which can be used as therapeutics in these cases is very limited. Tetracyclines can also exhibit severe side effects like, for example, phototoxicity or catabolic effects.
Other problems occuring with the frequent use of lactams are the increasing number of resistant bacterial strains isolated as well as an increasing number of patients which are allergic against .beta.-lactam antibiotics.